<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <div id="test"></div>

  <script src="../js/react.development.js"></script>
  <script src="../js/react-dom.development.js"></script>
  <script src="../js/babel.min.js"></script>

  <script type="text/babel">
    class Login extends React.Component {

      handleSubmit =  (event) => {
        event.preventDefault(); // 阻止表单默认提交
        const {username, password} = this
        alert (`用户名是${username.value},密码是${password.value}`)
      }
      
      render () {
        return (
          <form action="http://www.atguigu.com/" onSubmit={this.handleSubmit}>
            用户名： <input type="text" name='username' ref={c => this.username = c} />
            密码： <input type="text" name='password' ref={c => this.password = c}/>
            <button>登录</button>
          </form>
        )
      }
    }
    
    // 渲染到页面
    ReactDOM.render (<Login/>, document.getElementById ('test'))
  </script>
</body>
</html>